Reverse Forecast Calculator

How do you calculate a Reverse Forecast bet?

A Reverse Forecast is two Straight Forecast bets on the same race covering both possible 1–2 orders of your two selections. It creates two lines: Selection A to beat B, and Selection B to beat A. Settlement in UK horse racing and greyhounds is normally based on the official Computer Straight Forecast (CSF) dividend declared for the winning order. Only the line that matches the actual 1–2 order is a winner; the other line loses. Calculations therefore hinge on your unit stake per line and the dividend for the winning order.

What stake do I enter and how is it split between lines?

Enter the stake as a unit-per-line amount when placing a Reverse Forecast. Because the bet comprises two lines, your total outlay is twice the unit stake. Some calculators offer a “Total stake” mode that splits the amount equally across both lines; either way, the logic is identical—two equal stakes across the two orders.

• Per-line stake mode: if you enter £5, your total stake is £10 (two lines at £5 each).
• Total stake mode: if you enter £12 total, the calculator assigns £6 to each line (two lines at £6 each).
• Rounding: stakes are handled to the nearest penny (GBP), ensuring the two lines sum exactly to your total stake.

Input mode	Entered amount (£)	Lines	Stake per line (£)	Total stake (£)
Per-line	3.00	2	3.00	6.00
Total	10.00	2	5.00	10.00
Total	7.50	2	3.75	7.50

Which odds formats are supported: fractional, decimal, or American?

The calculator accepts fractional (UK), decimal, and American odds for estimation and comparison. Final settlement for forecasts uses the official CSF dividend, not a direct multiplication of runner odds; odds formats are therefore most useful pre‑race for planning.

• Fractional to decimal: decimal = (a ÷ b) + 1 for fractional a/b.

American to decimal:

• For positive American +X: decimal = 1 + (X ÷ 100).
• For negative American −Y: decimal = 1 + (100 ÷ Y).

Implied probability:

• From decimal d: p = 1 ÷ d.
• From fractional a/b: p = b ÷ (a + b).

Format entered	Decimal	American	Implied probability
4/1	5.00	+400	20.00%
5/2	3.50	+250	28.57%
1/2	1.50	-200	66.67%
11/4	3.75	+275	26.67%

Note: Forecast returns are settled to the official CSF dividend for the winning order. Odds conversions above help you compare selections and create pre‑race estimates; they do not replace the declared dividend at settlement.

How are returns, total stake, and profit calculated?

For a Reverse Forecast settled to the official CSF dividend D for the actual 1–2 order, with unit stake per line s:

• Total stake T = 2 × s (two lines).
• Return R = s × D (only the winning-order line returns).
• Profit P = R − T.

If a non‑runner leads to the bet being void before the off, UK bookmakers typically void both lines of a Reverse Forecast and return the stake; in that case R = T and P = 0. If there is a Rule 4 deduction pre‑off, the official CSF dividend will reflect the revised market; when using pre‑race estimation, apply the Rule 4 factor to affected selections before estimating any notional dividend. For dead‑heats, settlement follows the dividend(s) declared for the published result.

Scenario	Unit stake s (£)	Lines	Total stake T (£)	Official CSF dividend D (£)	Return R (£)	Profit P (£)	Notes
Win (A–B result)	5.00	2	10.00	8.20	41.00	31.00	Only A–B line wins; B–A line loses.
Win (B–A result)	2.00	2	4.00	3.50	7.00	3.00	Only B–A line wins; A–B line loses.
Lose (not 1–2 in any order)	3.00	2	6.00	—	0.00	-6.00	No line matches the result.
Void (non‑runner before off)	4.00	2	8.00	—	8.00	0.00	Both lines voided; stake refunded.

Summary: a Reverse Forecast is two equal-stake forecast lines; settlement uses the CSF dividend for the actual 1–2 order. Your calculator output should always show Total stake, Return (including stake), and Profit, with any voids or deductions clearly identified per UK rules.

Horse racing or greyhounds: where does a Reverse Forecast make sense?

A Reverse Forecast (RF) is most useful when you strongly expect two runners to fill first and second but cannot confidently pick the exact order. This scenario appears frequently in UK greyhound races (six-runner fields) and in horse races where the market has a clear top two. Because an RF covers both 1–2 and 2–1, it costs twice a Straight Forecast (SF) stake but buys order insurance. Settlement for bookmaker forecasts in the UK generally uses the official Computer Straight Forecast (CSF) dividend for the winning order.

• Good fit: small or medium fields with two stand‑out contenders; strong pace/setup edge suggesting a pair will dominate.
• Less suitable: highly competitive big fields where the top two are hard to isolate; cases where you have a firm view on the exact finishing order (then an SF is more efficient).
• Greyhounds: RFs are common due to six-dog fields and clearer draw/early speed dynamics.
• Horses: RFs see value when two market leaders are well clear on ratings, recent form, or sectional times.

Straight vs Reverse Forecast: what’s the difference?

A Straight Forecast (SF) selects the exact 1–2 order; a Reverse Forecast is two SF lines on the same pair, covering both possible orders. The RF doubles your stake but reduces order risk. Only the line that matches the official 1–2 order is settled as a winner at the CSF dividend for that order; the other line loses.

Feature	Straight Forecast (SF)	Reverse Forecast (RF)
Selections	2 runners in exact order (A first, B second)	Same 2 runners, both possible orders (A–B and B–A)
Number of lines	1	2
Stake	Unit stake s	2 lines at s each (total 2s)
Settlement basis	Official CSF dividend for the exact A–B result	Official CSF dividend for whichever order actually wins
Return (win)	s × CSF(A–B)	s × CSF(winning order); other line loses
When to use	You have a strong view on order	You fancy the pair to fill 1–2 but not the order

In both horse racing and greyhounds, bookmakers publish the CSF dividend for the winning order after the result is official. An RF monetises your “paired dominance” view; an SF monetises your “exact order” conviction at lower total stake.

What is a Reverse Forecast Double and how is it settled?

A Reverse Forecast Double combines two RFs in different races into one multiple. Structurally, each RF has two SF lines; multiplying across two races creates four lines in total: (A–B with C–D), (A–B with D–C), (B–A with C–D), (B–A with D–C). You stake the same unit s on each of the four lines, so the total stake is 4s. Settlement multiplies the winning CSF dividends leg‑by‑leg for the matching order in each race.

• Lines and stake: 4 lines at s each ⇒ total stake T = 4s.
• Winning condition: Both races must produce a 1–2 comprising your named pair; exactly one of the four lines can win.
• Return: R = s × CSF(Race 1 winning order) × CSF(Race 2 winning order).
• Profit: P = R − T.

Example: s = £2, CSF in Race 1 for the winning order = 5.80, CSF in Race 2 for the winning order = 7.40. Total stake T = £8. Return R = 2 × 5.80 × 7.40 = £85.84. Profit P = £85.84 − £8 = £77.84. If either race fails to land the 1–2 with your pair, all four lines lose. If one leg is made void before the off under your bookmaker’s rules, affected lines are void; surviving lines typically settle as singles on the remaining race at its CSF dividend (check the operator’s rules for the exact treatment).

Do non-runners and dead-heats affect payouts?

Yes. Non-runners and dead-heats change settlement mechanics, but the calculator mirrors official outcomes using published dividends and common UK rules. Always verify the specific operator’s terms where you place the bet, as implementations can differ between firms.

Non-runners (pre‑off):

• Single RF: If one of your two selections becomes a non‑runner before the off, the forecast cannot be formed. Depending on the bookmaker, the RF is usually voided with stakes returned, or converted to a win single on the remaining selection at SP. Check house rules.
• RF Doubles/Multiples: Lines containing the void leg are void. Remaining leg(s) may settle as singles at the declared CSF for those races per the operator’s multiple‑bet rules.
• Reserves (greyhounds): If a reserve replaces a withdrawn runner, bets typically stand on the revised field; the CSF dividend will reflect the starters.

Dead-heats:

• Dead‑heat for second (e.g., A wins; B and C dead‑heat for second): Bookmakers publish CSF dividends for each valid winning forecast (A–B and A–C). If your line matches one of the declared outcomes, you are paid at that dividend.
• Dead‑heat for first (e.g., A and B dead‑heat for first): The computer dividend algorithm applies the official rules; where relevant CSF dividends are declared, settlement is to those; if no CSF can be declared for an exact order, standard dead‑heat rules on stake/return apply per the operator.

• Post‑race adjustments: Any stewards’ amendments to the official result are applied to CSF settlement once the result is made official.

Practical takeaway: Your calculator return for RFs is driven by the CSF dividend for the winning order. Non‑runners can void or convert the bet depending on the firm, and dead‑heats are handled via the published forecast dividends or, failing that, the bookmaker’s dead‑heat rules.

How to use our free Reverse Forecast Calculator?

The calculator is designed for UK horse racing and greyhounds to price Reverse Forecasts (RF) and RF Doubles quickly and transparently. Enter your two selections per race, choose odds format (fractional, decimal, or American), set your stake (per line or total), and, if needed, add a second race to build a Double. The tool returns total stake, estimated or official-dividend returns, and profit. Where available, use dead-heat and Rule 4 inputs to mirror official settlement conditions.

Enter runners and odds: quick input tips

Reverse Forecasts cover both possible 1–2 orders of your pair, so you do not need to specify first/second when entering names. Use the odds format you are most comfortable with; the calculator converts between fractional, decimal, and American automatically. For greyhounds, entering trap numbers alongside names helps avoid mix-ups (e.g., “T3 Swift Ace”).

• Runners: enter the exact racecard names to match the declared result; add saddle/cloth or trap numbers as a cue.
• Odds entry: fractional for UK familiarity (e.g., 7/2), decimal for quick probability checks (e.g., 4.50), American for comparability (+250).
• Stake entry: choose per-line stake if you plan a fixed unit per SF line; choose total stake to let the tool split it 50/50.
• Greyhounds: draws and early pace matter—log trap numbers; horses: note headgear/going if you keep notes in the comments field.

Input area	Accepted formats	Examples	Validation rules	Tip
Runner A / Runner B	Text (letters, spaces, digits)	“Chaselot”, “T3 Swift Ace”	Non-empty; avoid duplicates	Add cloth/trap to reduce errors
Odds (fractional)	a/b with positive integers	7/2, 11/4, 1/2	a ≥ 1, b ≥ 1	Use UK racecard prices
Odds (decimal)	Real number ≥ 1.01	1.50, 3.75, 5.80	Two to three decimals	Quick for probability (1/d)
Odds (American)	+X or -Y integer	+250, -200	|value| ≥ 100	Converts to decimal
Stake mode	Per line or Total	Per line = £3; Total = £10	GBP to nearest £0.01	RF uses two equal lines
Adjustments	Rule 4, dead-heat flags	Rule 4: 10p; DH: tick	Optional, when applicable	Mirrors official terms

Add multiple races: can I chain Doubles?

Yes—adding a second race creates a Reverse Forecast Double. Each RF expands into two SF lines; two races produce four lines in total. You stake the same unit on each line, so your total stake is four times your unit stake. Settlement multiplies the declared CSF dividends from both races for the winning orders. While the calculator can show how line counts grow, most UK bookmakers commonly accept RF Singles and RF Doubles; higher-order forecast multiples (triples/accas) are rarely available online and may be refused—always check house rules before placing.

• Single RF: 2 lines at stake s each ⇒ total stake 2s.
• RF Double: 4 lines at stake s each ⇒ total stake 4s.
• General pattern: with n races, lines = 2ⁿ; total stake = s × 2ⁿ (availability beyond Doubles varies by operator).
• Return formula (Double): R = s × CSF₁ × CSF₂ for the matching orders; profit = R − 4s.

Races included	Lines	Total stake multiplier	Winning condition	Return (example)
1 (RF Single)	2	2 × s	One race: your pair fills 1–2 in any order	R = s × CSF(order)
2 (RF Double)	4	4 × s	Both races: your pairs land 1–2	R = s × CSF₁ × CSF₂

Example: s = £2; Race 1 CSF (winning order) = 6.10; Race 2 CSF (winning order) = 4.80. Total stake = 4 × £2 = £8. Return = £2 × 6.10 × 4.80 = £58.56. Profit = £58.56 − £8 = £50.56.

Is there an app or offline mode for quick calcs?

The calculator is web-first and works on modern mobile and desktop browsers. You can speed access via “Add to Home Screen” on iOS or “Install app” on Android/Chrome. This creates an app-like launcher. Basic inputs and saved settings may be available from your device cache; however, fetching official dividends, live markets, or rule updates requires an internet connection.

• iOS (Safari): open the calculator, tap Share, choose “Add to Home Screen,” confirm the name, then tap Add.
• Android (Chrome): open the menu (⋮), tap “Install app” or “Add to Home screen,” then confirm.
• Desktop (Chrome/Edge): look for the “Install” icon in the address bar to create an app shortcut.
• Offline scope: you can enter runners and odds manually offline for planning; settlement using CSF needs connectivity to confirm official dividends.

Tip: If you regularly bet at race time, pre-load the page on Wi‑Fi before travelling. This ensures assets are cached and the calculator opens instantly; reconnect to confirm results and any adjustments (e.g., non‑runners, Rule 4) before settling decisions.

Does this calculator match UK bookmaker rules?

Yes—when you enter the official Computer Straight Forecast (CSF) dividend for the winning 1–2 order, our Reverse Forecast (RF) outputs align with standard UK settlement used by major operators. CSF is derived from the Starting Prices (SPs) of the relevant race and is uniformly applied across UK bookmaking for horse racing and greyhounds. Differences between operators generally arise from stake handling (e.g., free bets), acceptance of multiples, rounding, and specific house rules in non‑runner or dead‑heat scenarios. For consumer protection and consistency, UK‑licensed firms operate under the oversight of the [Gambling Commission](https://www.gamblingcommission.gov.uk).

Paddy Power and Ladbrokes: will results align?

They should, provided you mirror the official conditions. Both firms settle forecast bets to the published CSF dividend for the winning order, so if you input the same unit stake per line and the same CSF dividend, your calculator return will match bookmaker settlement (before any firm‑specific bonuses or stake types are applied).

• Settlement basis: CSF dividend for the actual 1–2 order in the race.
• Stake logic: an RF is two Straight Forecast lines; total stake is twice your per‑line stake.
• Rounding: UK online settlement is to the nearest penny (GBP); our calculator does the same.
• Potential sources of variance: use of free bet tokens, boosts, or promos (not reflected by our neutral calculator); post‑race amendments (we pay to the final official dividend you enter).

BetVictor vs Unibet vs Parimatch vs Betano: what differs?

Core settlement—paying RFs to the CSF dividend—is industry‑standard across UK‑regulated brands. Practical differences typically involve availability of RF Doubles online, how void legs in multiples are handled, maximum payout limits, whether free bets/boosts apply to forecast markets, and presentation/rounding details. Always check each operator’s published rules within their help/terms sections before placing multiples or using promotions.

Settlement aspect	UK baseline (industry standard)	Calculator behaviour	Notes
RF composition	Two SF lines (A–B and B–A) at equal stakes	Requires per‑line or total stake; splits 50/50	Total stake = 2 × unit stake
Dividend source	Official CSF for the winning 1–2 order (SP‑based)	User enters the published CSF dividend	Applies to horses and greyhounds
Return (RF single)	Unit stake × CSF(winning order)	Matches penny‑for‑penny	Non‑winning line loses
RF Double availability	Commonly offered; higher‑order multiples may not be	Supports Doubles (4 lines total)	Check brand rules for acceptance
Void (non‑runner pre‑off)	RF single usually void; in multiples, voided leg reduces	Voids affected lines; remaining legs settle as applicable	House rules detail exact treatment
Dead‑heats	Settle to declared CSF dividends for valid outcomes	User selects the relevant declared dividend	Separate dividends may be published (e.g., A–B and A–C)
Rounding	GBP to nearest penny	Nearest £0.01	Aligns with online settlement
Promotions (free bets/boosts)	Brand‑specific eligibility and terms	Not applied	Use the bookmaker’s own calculator for promo effects

In short, when you input the published CSF and use the same stake logic, your figures will line up across these brands. Differences emerge mainly where brand policies on multiples, maximum payouts, or promotional instruments intervene.

Race forecast calculators: when to use the bookie tool instead?

Use our calculator for neutral, rules‑accurate planning and for reconciling results to the published CSF. Switch to the bookmaker’s own calculator or betslip preview when the bet involves brand‑specific mechanics that affect settlement or display.

• Free bets and boosts: only the bookmaker tool reflects token handling, stake‑not‑returned rules, and boost multipliers.
• Payout caps and limits: if close to maximum returns, rely on the operator’s display to see any cap applied.
• Market availability: some brands restrict RF multiples online; their slip will confirm acceptance before you stake.
• Non‑runner conversions in multiples: brand betslips show how a void leg reduces (e.g., Double to Single).
• Currency/rounding specifics: for non‑GBP accounts or unusual rounding, the operator’s calculator is authoritative.

Best practice: plan with our tool, confirm with the bookmaker’s slip when promos or operator‑specific limits could change the outcome.

Why did forecast betting evolve from Tote slips to calculators?

Forecast betting moved from paper-based Tote slips and shop counters to calculators because settlement depends on an official Computer Straight Forecast (CSF) dividend for the winning 1–2 order, which is not a simple product of the runners’ odds. Modern tools standardise stake splitting across lines, mirror the declared CSF, and correctly handle non-runners, Rule 4 deductions, and dead-heats. This reduces errors, speeds up reconciliation, and improves transparency for both horse racing and greyhounds in the UK.

Which dead-end methods failed and why?

Several legacy or shortcut methods were used informally to “estimate” forecast returns before reliable calculators were common. They persisted for convenience but failed to match official outcomes once the CSF dividend was declared.

• Odds-multiplication heuristics: multiplying first and second favourites’ odds or using ad hoc scaling ignores how CSF is derived from Starting Prices (SPs) and market structure; results routinely diverge from the declared dividend.
• Printed forecast charts in newspapers: static tables couldn’t adapt to late non-runners, going changes, or market moves; they became inaccurate as soon as the field shifted.
• Mental arithmetic at the counter: quick but error‑prone, especially when splitting stakes across RF lines, applying penny rounding, or converting between fractional and decimal formats.
• Reverse‑engineering from win/place markets: attempting to infer a forecast payout from separate markets ignores correlation between runners and CSF mechanics; it’s not settlement‑valid.
• Rule‑of‑thumb “favourite–second favourite” scales: too coarse for real fields, joint‑favourites, or uneven SP gaps; failed frequently in greyhound six‑runner races with sharp draw effects.

Approach	Intended use	Main limitation	Why it fell short	Status
Multiply odds / rough product	Fast pre‑race estimate	Not how CSF is computed	Ignores SP‑based dividend mechanics and runner correlation	Unreliable; not settlement‑valid
Printed forecast tables	Handy pocket guides	Static; no live updates	Fails with late non‑runners, going changes, or price moves	Obsolete
Mental arithmetic at counter	On‑the‑spot returns	Human error and rounding	Stake splitting across lines and penny rounding cause mistakes	Superseded by digital tools
Win/place market inference	Model‑lite estimation	Misses joint dependence	Correlation between runners breaks separability assumptions	Not used for settlement

All of these shortcuts share a core flaw: they do not replicate the official CSF dividend. Calculators don’t guess; they align your stake logic with the published payout for the actual 1–2 order and show clear totals and profit.

Devil’s advocate: why not just calculate forecasts by hand?

In theory, for a single Reverse Forecast (two lines) you could compute returns manually once you know the CSF for the winning order. In practice, hand calculation breaks down under time pressure and edge cases.

• Pre‑race estimation: without the declared CSF, a manual guess is just that—a guess—often diverging from settlement.
• Multiples: RF Doubles create four lines; scaling to more races doubles lines each time (2ⁿ). Errors compound quickly.
• Adjustments: accurately applying Rule 4 deductions, dead‑heat treatments, and non‑runner policies by hand is error‑prone.
• Rounding: UK settlement is to the nearest penny; small arithmetic slips skew profit, especially across several bets.
• Audit trail: a calculator provides consistent stake/return breakdowns you can screenshot or export; mental math does not.

Accuracy, speed, and transparency: what do modern tools fix?

Modern forecast calculators standardise the core mechanics of Reverse Forecasts and RF Doubles, reduce friction, and help you reconcile to the official dividend quickly.

• Accuracy: mirrors RF structure (two equal lines) and multiplies the correct CSF dividend for the winning order; handles pennies precisely.
• Speed: instant conversion between fractional, decimal, and American odds; instant stake splits (per‑line vs total).
• Edge cases: inputs for non‑runners, Rule 4, and dead‑heats align results with common UK settlement practice.
• Transparency: explicit totals for stake, return (including stake), and profit; clear indication of which line(s) won or were void.
• Scalability: supports RF Doubles (four lines) with correct line staking and leg‑by‑leg settlement logic.
• Consistency: repeatable results across horse and greyhound races, matching the published CSF once the result is official.

The net effect is fewer mistakes, faster decisions, and outcomes that match what UK‑licensed bookmakers pay when they settle to the official CSF dividend for the winning 1–2 order.

Frequently Asked Questions

What is the Computer Straight Forecast (CSF) dividend and when is it available?

The CSF dividend is the official payout value for the exact 1–2 order in a race, published once the result is made official. Reverse Forecasts settle to the CSF for the winning order, so as soon as that figure appears in the race result feed you can calculate R = s × CSF, where s is your unit stake per line.

CSF vs Tote Exacta: what’s the difference and which applies to a Reverse Forecast?

Reverse Forecasts settle to the bookmaker CSF dividend, not the Tote Exacta pool dividend. For example, with a £5 unit stake, if CSF for the winning order is £8.20 your return is £41.00, whereas a Tote Exacta dividend of £10.30 would imply £51.50; these are different products and are not interchangeable.

Can I place an each-way Reverse Forecast?

No. Forecasts are win-only markets that pay solely on the exact 1–2 order; there is no each-way version. If you want place coverage, you must structure separate bets such as win/place singles or other permutations, because there is no place component in CSF settlement.

Are Reverse Forecasts offered ante‑post or only on day‑of‑race markets?

They are typically day‑of‑race only because settlement uses the CSF derived from Starting Prices after final declarations. Practically, bookmakers open forecast markets close to the off when SP formation is viable; ante‑post forecast availability is unusual and operator‑specific.

How do I bet three or more runners in forecast permutations and how many lines are there?

A combination forecast over n runners creates n × (n − 1) Straight Forecast lines because every ordered pair is a line. For example, three runners produce 6 lines and four runners produce 12 lines; staking £2 per line yields total stakes of £12 and £24 respectively.

What happens if I enter the same runner twice in a Reverse Forecast?

A forecast requires two distinct selections; the bet is invalid and usually voided if both names are the same. Valid calculators prevent duplicates and prompt you to select a different second runner so the two-line structure can be formed.

Does Rule 4 affect Reverse Forecast payouts and how should I model it?

You do not apply Rule 4 directly to the CSF; the official CSF already reflects withdrawals and price changes. For pre‑race estimation using odds, apply the R4 factor to decimals with d’ = 1 + (1 − R4) × (d − 1); for a 20p R4, 4.00 becomes 3.40 and 6.00 becomes 5.00 before you model any notional dividend.

How are Reverse Forecasts settled when there is a dead‑heat?

Bookmakers publish separate CSF dividends for each valid winning order and your payout uses the dividend matching your line. Example: A wins, B and C dead‑heat for second; if CSF(A–B) = £7.20 and CSF(A–C) = £6.80 with a £5 unit stake, your return is £36.00 or £34.00 depending on which second‑placed runner you backed.

What if a selection is withdrawn or disqualified—does the CSF or my payout change?

If a selection is a non‑runner before the off, the Reverse Forecast is usually void and stakes are returned; if the official result is amended post‑race, settlement adjusts to the amended CSF. For instance, with s = £2, if CSF is revised from £8.00 to £10.50 your return changes from £16.00 to £21.00.

Are there maximum payout caps on forecast markets?

Yes, many operators impose per‑market or per‑meeting maximum payouts that override calculated returns once a threshold is reached. Because limits and tiers vary by brand and event class, you must check the bookmaker’s published maximum payout table for forecasts before staking.

Can I use the Reverse Forecast Calculator in EUR or USD and does currency change the math?

The math is currency‑neutral; returns scale one‑for‑one in your account currency. If your calculation shows £41.00 and your bookmaker settles in EUR, the equivalent at 1.15 EUR/GBP is €47.15; bookmakers display and settle in your native currency without FX inside the bet.

Can I build an RF Double across mixed codes, for example one horse race and one greyhound race?

Yes; settlement multiplies the CSF from each race for the winning orders regardless of code. For s = £2, if Race 1 CSF = £5.80 and Race 2 CSF = £7.40, your RF Double return is 2 × 5.80 × 7.40 = £85.84 with a total stake of £8 across four lines.

How soon after the race can I compute an exact Reverse Forecast return?

As soon as the CSF for the winning order is published in the official result, the exact return is R = s × CSF. Without the CSF you can only estimate; once the dividend appears, the calculator output matches bookmaker settlement penny‑for‑penny.

Are Reverse Forecast winnings taxed in the UK or Ireland?

For individuals, betting winnings are not subject to income tax in the UK or Ireland; bookmakers fund taxation via duties on their side. If you bet from another jurisdiction, local tax treatment may differ and should be checked with that regulator or a tax adviser.

What is the breakeven CSF for a Reverse Forecast versus a Straight Forecast?

With unit stake s, an RF uses two lines so profit is positive only if CSF > 2.00; an SF is profitable if CSF > 1.00. Example: with s = £5, an RF’s total stake is £10 and returns are £5 × CSF; you need CSF above 2.00 to exceed £10 and show profit.

Can I settle to bookmaker prices if no CSF is declared, for example on some international meetings?

Some operators use alternative settlement such as an in‑house forecast algorithm or pool equivalent when no CSF is available, which can diverge from UK CSF logic. In such cases, use the bookmaker’s own slip or rules page because a CSF‑based calculator cannot guarantee parity.